Envelope flap moistening apparatus

ABSTRACT

A moistening apparatus for wetting the gummed surface of an envelope flap. The apparatus is one comprising a moistening blade having a discharge slot therein. Means are provided in the moistening blade to sense when an air pocket has formed therein. When this means senses the air pocket, a control is actuated to supply additional fluid to the blade to force the air pocket out of the system.

United States Patent 1191 Lahore et al.

[451 Sept. 16, 1975 1 ENVELOPE FLAP MOISTENING APPARATUS [75] Inventors:Walter T. Lahore, Stamford;

Richard A. Hallenbeck, Wilton, both of Conn.

[73] Assignee: Pitney-Bowes, Inc., Stamford, Conn.

[22] Filed: Oct. 10, 1974 [21] Appl. No.: 513,526

[52] US. Cl. 118/7; 118/32; 118/401; 156/441.5 51 Int. c1. B05C 11 105[58] Field of Search 118/7, 2, 32, 401, 410, 118/411; 156/441.5

[56] References Cited UNITED STATES PATENTS 1,894,427 l/1933 Ryan118/401 1,987,813 1/1935 Allen 118/32 2,167,257 7/1939 Wheeler, Jr.118/401 2,368,520 l/1945 Burckhardt et 31.... 1 18/401 2,369,314 2/1945Ryan 118/40] 2,372,742 4/1945 Ryan 1 18/401 3,707,059 1/1973 Carr et al118/7 3,810,779 5/1974 Pickett et a1 1 18/401 Primary Exam'irierMervinStein Assistant Examiner-Douglas Salser Attorney, Agent, or FirmWilliamD. Soltow, Jr.; Albert W. Scribner; Robert S. Salzman [57] ABSTRACT Amoistening apparatus for wetting the gummed surface of an envelope flap.The apparatus is one comprising a moistening blade having a dischargeslot therein. Means are provided in the moistening blade to sense whenan air pocket has formed therein. When this means senses the air pocket,a control is actuated to supply additional fluid to the blade to forcethe air pocket out of the system.

5 Claims, 5 Drawing Figures BBQ-5.325

PATENTEBSEP 161975 SHEET 1 [1F 2 Pmmggsmms 3,905,325

SEMI 2 OF 2 Fis. 4.

H'SVAC 1 ENVELOPE FLAP MOISTENING APPARATUS" P The invention is for animproved envelope flap moist- I ening apparatus of the blade dischargetype as used generally in mailing machines, and more particularly for anenvelope flap blade moistening apparatus having BACKGROUND OF THEINVENTION.

Heretofore, the use of blade-like moisteners having a capillary-likeslot for wetting the gummed surface of an envelope flap were beset witha rather disturbing problem. If an air pocket would be caused to form inthe moistening blade, the blade would cease to supply moistening fluidto any subsequent envelope flaps passing in contact with the blade slot.This often occurring condition required that the operator of the mailingmachine incorporatingthe moistener had to be on constant guard toprevent a large volume of mail from being processed without beingproperly sealed. If the operator was not diligent, the letters'wereeither mailed without being sealed, or if discovered in time, wouldstill require a time consuming rescaling operation.

Obviously then, there has been a need for preventing or eliminating theformation of air pockets in blade moisteners. The present invention isdirected to this need.

SUMMARY or THE INVENTION This invention relates to blade-like moisteningdevices having a'capillary slot which wets the gummed surface ofenvelope flaps passing contiguously thereof. The blade rnoistener issupplied fluid by a reservoir, whose water level is maintained slightlybelow the slot of the moistening blade. Thereservoir and blade areconnected by a conduit having a priming pump disposedtherein.

iEnvelope flaps passing contiguously of the blade will causewater to becontinuously drawn from the reservoir-by capillaryaction. In thoseinstances where an air pocket forms in the blade it is necessary toprimethe blade. To this end, a pump is provided in the conduit to supply apriming charge of fluid to the moistening blade.

A solenoid attached to the plunger of the pump is actuated every time anair pocket is sensed, thus automatically supplying the prime. Thesensing mechanism of the invention comprises a thermistor which islocated in the well of the moistening blade. The thermistor forms partof a voltage divider circuit that controls the solenoid.

When the thermistor is surrounded by water, as when there is no airpocket in the supply line, the cooling effect of the surrounding liquidcauses the thermistor to 2 It is another object of the invention toprovide means for automatically sensing drynessand controlling thepriming .of fluidsupply to a moistening blade;

have a high resistance. In this condition, the solenoid remainsinactuated.

When an air-pocket forms in the supply line, the thermistor loo'ses'thecooling effects of the liquid, and is caused to immediatelyheat up. Inso doing, the resistance of the thermistor is caused to drop, and thesolenoid controlling the pump is actuated. Thus, the prim ing pumpautomatically supplies a priming-charge to the moistening blade everytime an air pocket-forms.

It is an object of this invention to provide an improved moisteningapparatus of the blade type;

ltis still another vobject of this invention to provide a means forsensing and controlling'the formation of air pockets in the moisteningblade.

These and other objects of the invention will be be t ter understood andwill become more apparent with reference to the following detaileddescription taken in conjunction with the 'attacheddrawings, in which:

FIG. 1 is a perspective -view 'of the envelope flap moistening bladeapparatus of this. invention; v

FIG. 2 is an enlargedview of the moistening blade of FIG. 1, showing acutaway-portion revealing a thermistor disposed in the fluid well of theblade; 7 I

FIG. 2A is a sectional view of the moistening blade of FIG. 2; takenalong lines 2A-2A; v

FIG. 3 is a sectionalview of-the blade of FIG. 2, taken along lines 3-3;and y FIG. 4 is a circuit diagram of the sensing and control circuit ofthe invention shown in FIG. 1.

DETAILED DESCRIPTION Generally speaking, this-invention is for anenvelope moistening fluid is connected to the blade via a,con-

duit.-The level of the fluid in the reservoir is generally maintainedbelow the level of the discharge slot of the blade. Priming meanscomprising a pump is provided in the conduitfor supplying a quantity ofmoistening fluid to the blade, when the blade runs dry (loses.prime)Sensing means supported by'the blade senses this dry condition; Controlmeans operatively connected between the sensing means and the primingmeans causes the pump to supply the moistening blade with fluid inresponse to. the sensing of dryness in said moistening blade by thesensing means.

Nowreferring to- FIG. 1, an envelope 9 having a flap 12' is showndisposed atop of a feeder deck 11. The envelope 9 is:guided along thefeeder deck 11 by means of guide wall 10."The envelope 9 and its flap 12move (arrow14') alongv the feeder deck .11 in a feed path which bringsthe flap 12 into contiguous engagement with a moistening-blade 15. Theenvelope flap 12 has a gummed surface 16 facing upwardly towards a slot17 in the bottomof the moistening blade 15 (seeFIG.

2A). A spring guide 50 causes the gummed surface of flap 12 to come incontact with that slot 17. When the gummed portion 16 of the flap 12passes contiguously of the slot 17, water '18 contained within the slotis drawn out of the slot onto the flap. The gummed portion 16 of theflap is thusly wetted.

' As' water. is extracted from blade 15 itis replenished byfluid'contained in reservoir'19 (FIG. 1). The fluid level 20' ofreservoir 19 is maintained below the level of slot 17. This provides-aconcave meniscus 21 (FIG. 2A) in the fluid 18 of the slot. The purposeof this arrangement provides that the water supplied to blade 15 willnot continuously drip from the slot. Rather, the fluid will flow onlywhen extracted'bythe surface tension created by the affinityo'f thecontiguously passing envelope flap.

A conduit 22 connects the reservoir 19 with the blade as shown inFIG. 1. A priming pump 23 is connected into the line 22 betweenreservoir 19 and blade 15. The priming pump 23 is of the kind as can befound in mailing machine Model 5600, manufactured by Pitney-Bowes, lnc.,Stamford, Connecticut, the present assignee of this invention.

A solenoid 24 is connected to the plunger 25 of the pump 23 via pivotedlink 40. The solenoid 24 is controlled by a sensing and control circuit(FIG. 4) schematically depicted by block 26 of FIG. 1. Forming part ofthe sensing and control circuitry 26 is a thermistor 27, which isschematically shown connected to circuit 26 via line 28. The head of thethermistor element 27 is disposed within the fluid supply cavity 29 ofthe moistening blade 15 (see FIGS. 2, 2A and 3).

The fluid cavity 29 is achieved by making blade 15 hollow and sealingthis hollow space with a top cover plate 30 as shown in FIGS. 1, 2, 2Aand 3.

OPERATION OF THE INVENTION In normal operation, water or a similarmoistening fluid, will fill cavity 29 of the moistening blade 15 bymeans of priming pump 23. As water is drawn off slot 17 onto flap 12, itis continuously replenished by the capillary action of the slot drawingliquid from reservoir 19 via conduit 22.

In the event that an air pocket forms (loss of prime) in cavity 29,resulting in there being no water in slot 17 to moisten the envelopeflaps, thermistor 27 immediately heats up. Its electrical resistancedecreases, which actuates solenoid 24 via sensing and control circuit26. The actuation of solenoid 24 causes the priming pump to supply thecavity 29 with a quantity of fluid forcing the air pocket out of thesystem. The thermistor 27 once again being surrounded by water, willcool down. lts resistance will once again become high,and the solenoid24 will be de-actuated via circuit 26.

Now referring to FlG. 4, the sensing and control circuit 26 is shown.Thermistor 27 forms part of this voltage divider circuit as shown, alongwith resistor 42. The circuit is powered from a standard source of AC.current (115 V) via transformer 31, which transforms the voltage to 24Vin order to isolate this circuit from the main power line. Taking point32 as a reference, when the thermistor 27 is surrounded by water and isof high resistance, the voltage at point 33 will be lower than thereference point 32 maintaining SCR 34 in the off state. When thethermistor 27 heats up as when air surrounds the thermistor, itsresistance drops, and the voltage at point 33 will rise above thereference point 32. When this happens, SCR 34 will be in the on stateand current will flow through solenoid 24 as shown by arrow 43. The SCR34 acts to energize the solenoid 24 for as long a period of time as thethermistor resistance remains low. However, the pump 23 will be actuatedby the pull of solenoid 24, thus furnishing water to surround thethermistor. This will cause the thermistor 27 to cool and the resistanceto increase. A tension spring 35 (FIG. 1) acts to return the plunger 25,and hence the solenoid 24 to its original unenergized position.

A resistor 36 and a diode 37 are placed in circuit 26 to limit the gatecurrent of the SCR 34 within specificational limits. The resistor 38acts to limit the sensitivity of the SCR 34.

Indicator lamp 41 connected across the solenoid 24 provides a visualsignal to the operator of dryness or failure to regain prime.

Of course many changes of an obvious nature may occur to those skilledin the art. e.g.. a relay may be used in place of the solenoid 24. Thisrelay could be continually energized as long as the thermistor 27 was inair. The relay would be used to turn on a continuously acting pump, inorder to restore the prime. Such a continuous system might be moredesirable where a large air pocket is formed, requiring several pumpeycles to replenish the fluid supply.

Also, the indicator 41 may be replaced by means to de-actuate theenvelope feed mechanism, such that when the system runs dry, envelopeswill be prevented from being fed to the moistener apparatus.

These and other changes which would be obvious to the skilledpractitioner in this art are deemed to fall within the spirit and scopeof the invention as presented by the appended claims.

What is claimed is:

1. An envelope flap moistening apparatus, comprising:

means defining an envelope flap feed path;

a moistening blade extending into the envelope flap feed path and havinga discharge slot for dispensing moistening fluid to a gummed portion ofa contiguously passing envelope flap;

a reservoir operatively connected to said blade and containingmoistening fluid for said moistening blade, a level of said moisteningfluid in said reservoir generally disposed below a level of thedischarge slot in the moistening blade;

priming means operatively connected between said reservoir and saidmoistening blade for supplying a quantity of moistening fluid to saidmoistening blade, when said moistening blade runs dry;

sensing means supported by said moistening blade for sensing when themoistening blade runs dry; and

control means operatively connected between said sensing means and saidpriming means for causing said priming means to supply the moisteningblade with fluid in response to the sensing of dryness in saidmoistening blade by said sensing means.

2. The envelope flap moistening apparatus of claim 1, wherein saidsensing means comprises a thermistor disposed within the moisteningfluid being supplied to said moistening blade, said thermistor changingresistance in response to a lack of fluid surrounding said thermistor,which resistance change causes the control means to operate said primingmeans to supply said moistening blade with fluid.

3. The envelope flap moistening apparatus of claim 2, wherein saidpriming means comprises a solenoid actuated pump for discharging aquantity of fluid to said moistening blade and wherein the control meanscomprises a voltage divider circuit operatively comprising saidthermistor as an operative. element thereof.

4. The envelope flap moistening apparatus of claim 3, wherein thesolenoid actuated pump is maintained in actuation by a SCR as long asthe thermistor continues to sense a dryness in the moistening blade.

5. The envelope flap moistening apparatus of claim 3, wherein anindicator means is disposed in the voltage divider circuit to indicatewhen the moistening apparatus requires fluid.

1. An envelope flap moistening apparatus, comprising: means defining an envelope flap feed path; a moistening blade extending into the envelope flap feed path and having a discharge slot for dispensing moistening fluid to a gummed portion of a contiguously passing envelope flap; a reservoir operatively connected to said blade and containing moistening fluid for said moistening blade, a level of said moistening fluid in said reservoir generally disposed below a level of the discharge slot in the moistening blade; priming means operatively connected between said reservoir and said moistening blade for supplying a quantity of moistening fluid to said moistening blade, when said moistening blade runs dry; sensing means supported by said moistening blade for sensing when the moistening blade runs dry; and control means operatively connected between said sensing means and said priming means for causing said priming means to supply the moistening blade with fluid in response to the sensing of dryness in said moistening blade by said sensing means.
 2. The envelope flap moistening apparatus of claim 1, wherein said sensing means comprises a thermistor disposed within the moistening fluid being supplied to said moistening blade, said thermistor changing resistance in response to a lack of fluid surrounding said thermistor, which resistance change causes the control means to operate said priming means to supply said moistening blade with fluid.
 3. The envelope flap moistening apparatus of claim 2, wherein said priming means comprises a solenoid actuated pump for discharging a quantity of fluid to said moistening blade and wherein the control means comprises a voltage divider circuit operatively comprising said thermistor as an operative element thereof.
 4. The envelope flap moistening apparatus of claim 3, wherein the solenoid actuated pump is maintained in actuation by a SCR as long as the thermistor continues to sense a dryness in the moistening blade.
 5. The envelope flap moistening apparatus of claim 3, wherein an indicator means is disposed in the voltage divider circuit to indicate when the moistening apparatus requires fluid. 